Setting air brake trip
speed
Selecting speed range letter other than
bypass will activate air brake Air brake will
stop air motor from operating if threshold
speed setting is exceeded Air motor will not
restart until intentionally reset Cause of
pump overrun may be anything that will
allow pump to run faster than normal such
as, but not limited to the following:
Cavitation
Low fluid levels will allow pump to cavitate
Pump will try to pump air instead of fluid into
fluid lines
Broken hose or fitting
Broken hose or fitting will cause loss in fluid
pressure allowing pump to run faster than
normal
Setting speed
1
Remove selector cover (
87
) by removing
screw (
88
) to gain access to selector
knob (
84
)
2
Select bypass mode by positioning
selector knob pointer (small round hole
in face of selector knob) to face of
labyrinth cover (
78
)
3
Determine speed of pump by counting
number of strokes pump makes per
minute with pump and air motor
operating normally
4
After determining normal operating
speed of pump and air motor, consult
setting legend on face of labyrinth
cover (
78
), and find speed range closest
to normal operating speed of air motor
5
To allow for normal fluctuation in
operating speed of air motor and pump,
set selector knob to next highest speed
setting
6
Test pump in operation to make sure it is
operating properly before leaving
pumping system unattended
Speed settings
Bypass air brake In bypass mode air
brake does not provide any protection to
pump or air motor Air motor will
continue to run at any speed
See
Fig. 13
1
45 to 60 cycles/minute, air brake will trip
turning off air motor when air motor
speed reaches speed of
45 to 60 cycles/minute
2
30 to 45 cycles/minute, air brake will trip
turning off air motor when air motor
speed reaches speed of
30 to 45 cycles/minute
3
20 to 30 cycles/minute, air brake will trip
turning off air motor when air motor
speed reaches speed of
20 to 30 cycles/minute
4
15 to 25 cycles/minute, air brake will trip
turning off air motor when air motor
speed reaches speed of
15 to 25 cycles/minute
5
10 to 20 cycles/minute, air brake will trip
turning off air motor when air motor
speed reaches speed of
10 to 20 cycles/minute
6
5 to 15 cycles/minute, air brake will trip
turning off air motor when air motor
speed reaches speed of
5 to 15 cycles/minute
1)
2)
Air brake operation
NOTE
Speed settings are not precision speed con-
trol settings for air motor All speed settings
are approximate and are not intended for use
in precisely controlling speed of pump/pump
tube combination Precision control of pump
operating speed is beyond scope of device
NOTE
Operating air motor at speeds greater than
45 cycles/minute is not recommended with
air brake engaged Operation at speeds
greater than 45 cycles/minute will cause no
harm to air brake, but may exceed limitations
of timing circuit in air brake causing air brake
to trip without apparent cause
Fig. 13
1)
Speed setting legend
2)
Speed setting dial
NOTE
Always shut off air supply before servicing air
motor Air motor in tripped condition is under
pressure and may restart unexpectedly for
one or two cycles
9
